<template>
 <div class="todo-footer" v-show='total'>
        <label>
          <input type="checkbox" v-model="isAll"/>
        </label>
        <span>
          <span>已完成{{doneTotal}}</span> / 全部{{total}}
        </span>
        <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
      </div>
</template>

<script>
export default {
  name:'Myfooter',
  props:['todos'],
  computed:{
    total(){
      return this.todos.length
    },
    doneTotal(){
      /* const x=this.todo.reduce((pre,current)=>{
         console.log('@',pre,current);
         return pre+(current.done?1:0)
      },0)
      */
    return this.todos.reduce((pre,current)=> pre+(current.done?1:0),0) 
    
    },
    // 控制全选框
    isAll:{
      // 全选框是否勾选
      get(){
          return this.doneTotal=== this.total  && this.total > 0
      },
      // isAll被修改时set被调用
      set(value){
        //  this.checkAllTodo(e.target.checked)
       this.$emit('checkAllTodo',value)
      }
    },
  },
  methods:{
   /* checkAll(e){
      this.checkAllTodo(e.target.checked)
    },
    */
    
    clearAll(){
       confirm('确定清除所有已完成的事项？'),this.$emit('clearAllTodo')
  }
}
}
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}

</style>